1. Field of the Invention
The present invention relates to a block unit for repairing flow passage facilities, and to a method of repairing flow passage facilities using the block unit.
2. Description of the Related Art
When an underground pipe, such as pipelines and passageways, becomes defective or too old to perform properly, the pipe is repaired and rehabilitated without digging the earth to expose the pipe and disassembling the sections of the pipe. This non-digging method of repairing an underground pipe has been known and practiced commonly in the field of civil engineering. The pipe lining method utilizes a tubular pipe liner bag that is made of a resin-absorbent material impregnated with a hardenable resin and has the outer surface covered with a highly air-tight plastic film. The tubular pipe liner bag is inserted into a pipe to be repaired by means of a pressurized fluid such that the pipe liner bag is turned inside out as it proceeds deeper in the pipe. Hereinafter, this manner of insertion shall be called “everting.” When the entire length of the tubular liner bag is everted (i.e., turned inside out) into the pipe, the everted tubular liner is pressed against the inner wall of the pipe by a pressurized fluid, and the tubular flexible liner is hardened as the hardenable resin impregnated in the liner is heated, which is effected by heating the fluid filled in the tubular liner bag. It is thus possible to form a plastic pipe within the pipe to repair the same.
In the pipe lining method as described above, a service fluid such as sewage must be temporarily stopped or be bypassed around a portion of the pipe subjected to the repair in order to prevent the service fluid from flowing therethrough.
However, since a large amount of service fluid must be bypassed, particularly, in the event of repairing a pipe having a large diameter, the repair operation encounters difficulties in installing large scale facilities for bypassing the service fluid.
To solve this problem, there has been proposed a method of repairing a pipe while a service fluid is passed therethrough. Specifically, this method involves introducing a small cylindrical tube having an outer diameter smaller than the inner diameter of the pipe from a manhole into the entrance of the pipe, pushing the short tube with a hydraulic jack or the like for insertion into the pipe, and repeating this operation to repair the pipe.
However, when the foregoing method is applied to a pipe having a large inner diameter (for example, 600 millimeters or more), the short tube used in this method also has a large diameter. This short tube has too large of a diameter to fit through a manhole.